Intraocular pressure change after myopic laser in situ keratomileusis as measured on the central and peripheral cornea

Background: Laser in situ keratomileusis (LASIK) leads to inaccurate measurement of intraocular pressure (IOP). This study aimed to determine the efficacy and reliability of IOP measurement on the peripheral cornea after LASIK. Methods: The IOP was measured in 52 eyes of 26 subjects before LASIK and one week and one month after LASIK using non-contact tonometry. The measurements were made on the central and peripheral cornea and the results were subjected to statistical analysis. Results: The mean measured IOP on the central cornea was decreased by 6.425 +/- 2.544 mmHg at one week and 5.752 +/- 3.863 mmHg at one month post-operatively. The mean IOP measured on the peripheral cornea was decreased by only 0.921 +/- 2.054 mmHg at one week post-operatively. Most notably, the mean IOP measured on the peripheral cornea was increased by only 0.158 +/- 2.979 mmHg at one month post-operatively with no statistical significance (p > 0.05). Furthermore, a linear regression of ablation depth versus change in IOP measured on the central cornea was demonstrated, but the peripheral IOP did not display such a statistically significant correlation with the depth of ablation at both one week and one month after operation. Conclusion: The IOP measured on the peripheral cornea is closer to the actual IOP. Therefore, it is more accurate and reliable to measure IOP on the peripheral cornea than on the centre after LASIK.